Anesthetizing irrational phobias away

Research shows that a simple injection of local anesthetic into the part of …

According to the National Institute of Mental Health, somewhere around 10 to 20 percent of Americans suffer from some form of a phobia. When the sufferer is exposed to the object they fear, problems can range from mild anxiety to full-fledged panic attacks. New research from Hiroshima University suggests that that irrational fears may be blocked with the help of a common anesthetic. The article that describes the results is published in the open access journal Behavioral and Brain Functions.

The experimenters trained commercially available goldfish (Carassius auratus) to be afraid of light flashed in their eyes by having a flash of light followed by a low-voltage electric shock. After a conditioning period, the researchers could monitor the fish's heart rate and see it drop in response to the stimuli—in a manner analogous to a human's heart rate rising during a fear response—even in cases where there were no negative consequences.

The researchers were able to show that, after an injection of a small amount of lidocaine directly into the corpus cerebelli, the fish were unable to learn to be afraid. That is, once the lidocaine took effect, the conditioning of the fish to associate the flash and electric shock no longer took. Future flashes didn't slow the heart rate although, once the lidocaine wore off, the fish were still able to learn to be scared of the conditioned trigger.

Now, any connection to humans may seem tenuous, but the vermal part of a mammal's cerebellum has been suggested to be homologous to the corpus cerebelli in fish. This may make the fish a useful model for studying ways of limiting the impact of phobias.

24 Reader Comments

A phobia as an irrational fear of something. However, a direct respnse (in this case pain after light and hence fearing light), seems very rational. This study seems to be more concerned with conditioned response rather than phobia. In fact, the paper never mentions phobia, so I dont know if it's correct to draw the conclusion that this would somehow help with irrational behavior. It seems more likely that the lidocane is just retarding the learning process.

Fearless warriors are failures. Both Sun Tzu (Art of War) & Miyamoto Musashi (Book of Five Rings) said that fear is what keeps warriors alive. Fear is what keeps your troops motivated to use a tactical battle plan rather than a suicidal one. Fear is what ensures your enemy will surrender after they've been shown irrefutable evidence of your tactical might. You don't want them so afraid they will never fight, but you don't want them so fearless they will do stupid things.

Quote:

I have a phobia of having things injected into my brain!

Fish brains are like ... really f'ing small. How do they know it wasn't just the physical trauma on the brain of the needle getting shoved in? Or, the placebo effect of having a needle shoved in your brain? I'm sure the trauma of having a huge needle shoved in your brain would put many phobias into perspective.

Fish brains are like ... really f'ing small. How do they know it wasn't just the physical trauma on the brain of the needle getting shoved in? Or, the placebo effect of having a needle shoved in your brain? I'm sure the trauma of having a huge needle shoved in your brain would put many phobias into perspective.

While I know this was in jest, they actually showed in the paper how they knew they injected into the right places. In addition to the lidocaine, they injected some blue dye and then basically did a brain-ectomy on the fish once the experiment was over. In the side view of the brain you see the CC shining bright blue and the rest of the brain as white. It's pretty cool.

Lidocaine is a sodium channel blocker. When used in the skin, it blocks the sodium channels of nerve receptors, anesthetizing the skin. When used in the blood, it blocks the sodium channels of the heart, slowing conduction and improving arrhythmias. When used in the brain, it blocks the sodium channels of brain tissue, and in this case, blocking formation of new memories.

Nothing about this article has to do with anesthesia or phobia. It's about conditioned learning and blocking brain function with a sodium channel blocker.

Yeah, from the described experiment they weren't turning of a learned behavior, but preventing the learning of a new behavior. The application in humans would be applying the treatment to someone who knows they're going into a bad situation to avoid getting PTSD. If this blocks the fear response altogether, however, there would be some nasty side effects, like people acting stupid because they don't have even a rational amount of fear to keep them in check.

Nothing about this article has to do with anesthesia or phobia. It's about conditioned learning and blocking brain function with a sodium channel blocker.

This sloppy journalism is not worthy of Ars.

This is the second time this week that one of our writers has been criticized for using a term that appears in the title of the paper that is being covered. By following the DOI link at the bottom, you could confirm that the paper in question is "Effects of local anesthesia of the cerebellum on classical fear conditioning in goldfish." I'm not going to force my writers to edit out the use of a term that is used by the authors of the paper itself.

Now, you may have a point about the degree to which learned associations are associated with phobias, but my understanding is that some of the known fears have nothing to do with a direct threat (since, frankly, some of the objects of unjustified fears are simply not threatening), but may be the product of an associative memory. Which is what's at play here.

If my understanding (and, apparently, by extension, Matt's) is wrong here, it would be good of you to explain why, and provide some pointers to more information on the topic. As it is, all i can tell is that you're annoyed, but not whether you have good reason for your annoyance.

Dr. Jay, "mbfhdhpzvq" is obviously wrong that this has nothing to do with anesthesia(!) but the headline "Anesthetizing irrational phobias away" is a stretch at best. The word Phobia doesn't appear in the research, not does the research show that fear (or phobias) can be "anesthetised away" (ie removed once formed), but rather that fear conditioning can be blocked. That the goldfishes' fears were irrational wasn't really the point, the way I read it.

There's nothing in there to suggest that a phobia can be "turned off", as suggested in the opening paragraph.

Anesthesia is the term used for being without sensation. Lidocaine provides anesthetic effect in the skin because of the sodium channels in skin/soft-tissue pain fibers being blocked, but it has absolutely no anesthetic effect in the brain. After all, there are zero pain fibers within brain matter. All lidocaine in this experiment is doing is blocking or diminishing the neurotransmission of neurons involved in cerebellar pathways, and again absolutely nothing to do with anesthesia. In science, terminology matters. Get it right. Otherwise, it's "sloppy".

Bottom line: you f*** with the brains of fish, and it disturbs expected behavior. Whoopty-doo. However, I don't blame Ars as much as I blame these third-rate Japanese researchers and the translation service for this piece of work. This article is weak.

Dr. Jay, I expect your authors to actually read the article, use rudimentary critical reading skills, and point out the details shown with appropriate criticism. Journal articles aren't press releases.

Damn, I had a few questions in some comments that got baleeted. Let me try again:

So does this method wipe out the previously learned fear, temporarily prevent a previously learned fear from happening, or just prevent a learned fear from forming while under the influence of the anesthetic?

I have to say that while I disagree with the tone, "mbfhdhpzvq" has a very good point, though perhaps focusing on the method (sodium channel blocking) is less important than the simple facts that:

1) this is not "anesthetizing irrational phobias away" (a phobia being a pre-existing association) but rather "interfering with the normal functioning of a particular brain area happens to inhibit pavlov conditioning"

2) about the only interesting thing here (IMO) is the use of lidocaine to achieve the effect. If you mess with an area of the brain, that area is not going to function properly. Perhaps the title might have been "Lidocaine injection directly into the brain proves to be a useful method of altering brain function."

3) you spelt lidocaine rong :-)

Of course, there are good science reporting days... and then there are days you write up papers like this because nothing else seemed more interesting. Still, it could have been better. This isn't Wired - you don't need to bend the truth or get hyperbolic or interpret in a questionable yet "more interesting to the layman" fashion in order to keep your audience interested. We come here for the quality.

Perhaps the title might have been "Lidocaine injection directly into the brain proves to be a useful method of altering brain function."

3) you spelt lidocaine rong :-)

No no, it was spelt correctly: Lido cane, the cane from Lido. Injecting a cane into the brain certainly alters brain function. It is similar to injecting a 9 mil into the brain, as far as brain function altering effects are concerned Usefulness of such effects is open to discussion; but, then again, it always is.

I have to say that while I disagree with the tone, "mbfhdhpzvq" has a very good point

++ I actually think the guy with a jumble of letters for a handle articulated his point well the first time. I would have liked to see the criticism phrased more constructively, but as far as I can tell he's accurate on the science. Please don't be afraid of being critical toward the research, Ars.

I was not aware that the corpus cerebelli (the central part of the cerebellum) was a cognitive fear center. More of a posture and tone center. Sounds to me like that all that is happening here is that the lido is acting as a beta blocker to prevent an increase in heartrate by direct action on autonomic control paths. This does not sound like a cognitive reduction in fear and would have occurred with a systemic dosage of any beta blocker that acted directly on the heart.

Beta-blockers and sodium-channel blockers use completely different mechanisms of action.

While possible that the lidocaine diffused systemically in the fish causing delayed heart conduction, the authors stated that lidocaine injected did not alter heart rate when no other stimulus was present.

Ok, several things here. The easiest is that i think we now have the same (correct) spelling of lidocaine throughout.

Item 2 is the significance of this work. Right now, most studies of fearful associative learning are carried out in rodents, which is both expensive and, in various ways, inconvenient. This paper seems to indicate that it's possible to perform similar experiments in fish, which could be helpful. Matt, who doesn't work in neurobiology, also just found it interesting when he read the paper; since most of our audience doesn't work in neuro either, there's a reasonable chance they would as well, even if it's not cutting edge.

The fact that Matt doesn't work in neuro leads us to the next point: if we're going to restrict people to writing about things that they can analyze better than peer reviewers can, you're simply not going to be seeing much content on NI. (For example, i'd be limited to handling genetics and developmental bio, and we might just as well fire Casey Johnston.) Like it or not, this means that, for a lot of our coverage, we have to expect that the peer reviewers have done their jobs.

(As an aside, peer review tends to be more thorough in places like Nature and Science, and we bias our coverage in that direction for various reasons. But i'd rather not see NI become limited to a rehash of big name journals.)

This is also related to the use of the term anesthesia. As most of you presumably know, many fields of science use definitions of terms that differ from the common understanding. The use of the term anesthesia in the title of this paper seemed to use a definition of chemically limiting neural activity, which doesn't seem so outrageously off from common usage that it set off alarm bells. Again, if our coverage were provided by someone currently doing neuro, we might have recognized that this isn't the case, but you can see above for thoughts on that.

This isn't an attempt to say that this was a great post, or that we're not going to take some of the informed criticism on board. What i'd like to ask is that the readers keep the challenges of producing content for NI in mind, recognize that a significant amount of our content won't always satisfy someone who knows a field better than we do, and keep the criticism informed and productive so that we can learn from it.

Huh? I think a lot of people are just trying to say that Matt wrote this up as potential phobia cure when the research looks more like phobia prevention. That's all, really.

Decision to cover it was fine, can't say it was a waste of my time to read or anything... and the depth was about the same as when you cover, say, astronomy Dr. Jay. Which is usually a fuzz past my level of knowledge, so I still learn something

Matt Ford / Matt is a contributing writer at Ars Technica, focusing on physics, astronomy, chemistry, mathematics, and engineering. When he's not writing, he works on realtime models of large-scale engineering systems.